AB0854 CLINICAL CHARACTERISTICS OF PATIENTS WITH AMINOACYL-tRNA SYNTHETASES COMPARED WITH OTHER MYOSITIS ANTIBODIES IN A COHORT OF INFLAMMATORY MYOSITIS
Authors: M. H. Kim
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> The Idiopathic Inflammatory Myositis (IIM) are heterogeneous with different clinical profiles associated with various myositis autoantibodies. Among the Myositis specific antibodies (MSA), antibodies against aminoacyl-tRNA synthetases(ARS) is related to the clinically unique IIM subsets, Antisynthetase syndrome(ASS). <h3>Objectives</h3> The aim of this study was to identify the prevalence and clinical features of patients with ARS autoantibodies compared with other myositis antibodies in a single center cohort of IIM in Korea. <h3>Methods</h3> Adult patients diagnosed with IIM and positive for myositis antibodies were recruited in the myositis cohort from January 2020 to December 2022. Retrospective analysis was performed based on the clinical data including clinical features, laboratory data, high-resolution CT (HRCT) findings, and pulmonary function manifestations. <h3>Results</h3> Among 82 patients, 25 patients were positive for ARS autoantibodies and 57 patients had other myositis antibodies. The most common ARS antibody was anti-EJ (n=10) followed by anti-PL-7 (n=8). MSA other than ARS antibodies included anti-SRP (n=6), anti-TIF1γ (n=11) and anti-MDA-5(n=19). Anti-Ro52 was detected in 48 patients and 79.2% of which were accompanied by other antibodies. The most common clinical manifestations of patients with ARS antibodies were respiratory symptoms, more commonly experienced than patients with other myositis antibodies (84% vs. 47.4%, p=0.002). Meanwhile, muscle weakness (32.0% vs. 61.4%) and dysphagia (8.0% vs. 33.3%) were less frequently exhibited compared with those with other myositis antibodies. In regard to laboratory findings, the ARS antibodies positive group showed higher inflammatory markers than other myositis antibodies group, the mean (SD) of erythrocyte sedimentation rate (ESR) was 53.6 (34.6) and 33.8 (24.3), respectively. Anti-Ro52 and anti-nuclear antibodies (ANA) cytoplasmic pattern were more detected in the ARS antibodies positive group. Interstitial lung disease (ILD) was also more commonly detected in patients with ARS antibodies than other myositis antibodies group (88.0% vs. 59.6%) and non-specific interstitial pneumonia (NSIP) was the most frequent pattern of ILD. However, there were no significant differences in the baseline pulmonary function between the two groups. <h3>Conclusion</h3> Patients with ARS antibodies experienced more respiratory symptoms while muscle weakness is less common clinical manifestations than patients with other myositis antibodies. Moreover, higher inflammatory markers and ANA cytoplasmic pattern along with Anti-Ro52 were more commonly detected in the ARS antibodies positive group. <h3>References</h3> [1]DA SILVA, Lila Morena Bueno, et al. Demographic, clinical, laboratory data, prognostic, and treatment features of patients with antisynthetase syndrome: An international, two-center cohort study. Archives of Rheumatology, 2022, 37.3: 424-434. [2]GUPTA, Latika, et al. Myositis-specific and myositis-associated autoantibodies in a large Indian cohort of inflammatory myositis. In: Seminars in Arthritis and Rheumatism. WB Saunders, 2021. p. 113-120. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.